Forced circulation

Definition - What does Forced circulation mean?

Forced circulation is a type of circulation that is mostly present in boilers and evaporators. This process is employed in areas where scaling, thermal degradation and other negative impacts may occur.

In the process, liquids are circulated at very high rates across the heat exchanger, preventing boiling. The heated liquid goes into a separator with lower pressure, where it undergoes flashing and concentration.

Corrosionpedia explains Forced circulation

Forced circulation differs from natural circulation as it largely depends on pumps instead of natural density differences, for water circulation in boilers. In a system that operates under forced circulation, the solution that should undergo crystallization or evaporation goes into circulation pumps.

The solution is then transferred to heat exchangers with elevated velocity levels all the way from the base to the top. In boiling surfaces, adequate volume retention guarantees minimal nucleation and at the same time, the development of the necessary size of crystal.

The utilization of a forced circulation system can be a cost-efficient alternative, especially when the size of the product is not that important. Furthermore, tools like evaporators and boilers that operate on forced circulation can be widely used when there is dominant evaporation rate. It is most suitable for solutions containing salt, wherein the solubility is not that dependent on variables, such as temperature.